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The enclosure and ungrazing practices for grassland management result in accumulation of plant litter on soil surface thus affecting the available soil water and nutrients for plant production. We experimentally investigated the effects of litter on soil properties and plant growth in a prolonged enclosure grassland of Loess Plateau, China. Three different litter manipulations were conducted including removal of all litter, an untreated in-situ control with original litter levels, and a double litter treatment. Litter treatment experiments demonstrated that plant litter affected the superficial soil water. Soil water content in plots with in-situ or double litter is generally higher than that with litter removal. The depletion of soil water up to five days post rainfall is fastest in litter removal plots for the top soil, but no evident difference for the deep ones. Different litter treatments have no significant impact on soil total carbon, nitrogen as well as carbon/nitrogen ratio for consecutive two years experiments. Both above- and below-ground biomasses in plots of litter removal were less than those in the plots of in-situ and double litter treatment. Litter affects plant production mainly through the mechanical barrier regulating root zone soil moisture. Therefore, prolonged litter manipulation experiments are desirable to understand the long-term response of plant growth on litter from nutrient aspect. [ABSTRACT FROM AUTHOR]

Processing tomatoes are major cash crops in the Hetao Irrigation District, Inner Mongolia, China. Conventional irrigation practices have resulted in ecological and environmental problems due to the specific climate and groundwater conditions. Field experiments were conducted to investigate the effects of water stress on processing tomatoes yield, quality, and water use efficiency with plastic mulched drip irrigation in sandy soil of the Hetao Irrigation District. Tomatoes were irrigated at 40%, 60%, 70%, 80% and 100% of crop evapotranspiration (ET c ). Results showed that soil water content and salt concentration mainly varied in the upper 60 cm soil layer. Dry aboveground biomass and yield increased with increased ET c to 80 or 100%. The highest yield was obtained with 80% ET c treatment both years (70 and 81 t/ha). Increasing water stress led to the increase of soluble solids content and Vitamin C. Actual evapotranspiration (ET a ) ranged from 188 to 323 mm in the two seasons, and increased quadratically when the irrigation depth increased to 80% ET c . The highest water use efficiency (WUE) was found at 60% ET c treatment in 2013 and 80% ET c treatment in 2014. Comprehensive analysis of yield, WUE and ET a , irrigated at 80% ET c was recommended as the optimal irrigation strategy in the sandy soil of the Hetao Irrigation District. [ABSTRACT FROM AUTHOR]

Greenhouse gas emissions from agricultural soil are strongly affected by the field practices including fertilization, irrigation and cultivation model. Understanding the mechanism of greenhouse gas emissions from soil and their impact factors is essential for cleaner agricultural production and global greenhouse gas mitigation. This paper investigated greenhouse gas emissions from soil of mulching cultivated maize (Zea mays L.) field under different irrigation and fertilization regimes. Border and drip irrigation with different schedules were implemented in the upper reaches of Yellow River, China. Border irrigation included three different irrigation depths (180, 315 and 450 mm), and drip irrigation was controlled by a tensiometer and triggered by three different matric potentials (−15, −25 and −35 kPa). Three nitrogen fertilizer levels (350, 250 and 150 kg ha−1) were applied for the drip irrigation triggered by the matric potential of −25 kPa. Soil acted as a sink of CH 4 in the semiarid site regardless of irrigation and nitrogen fertilization regimes. Irrigation scheduling had no significant influence on CO 2 emissions, but the irrigation method did have. Cumulative CO 2 emissions increased by 24.7% for drip irrigation compared with border irrigation at the same water and nitrogen fertilizer levels. Cumulative CO 2 emissions for the high nitrogen fertilizer treatment (350 kg ha−1) increased by 19.3% in comparison with the medium and low levels under drip irrigation. N 2 O emissions were positively related to the irrigation depth under both drip and border irrigation. Cumulative N 2 O emissions reduced by 23.5% for drip irrigation compared with border irrigation at the same water and nitrogen fertilizer levels. N 2 O emissions increased with the increase in nitrogen fertilizer application under drip irrigation. Drip irrigation with high frequency (−15 kPa) and medium nitrogen fertilization (250 kg ha−1) obtained the best economic and environmental performance through comprehensive evaluation of the yield, water and fertilizer productivity, global warming potential, greenhouse gas intensity and net ecosystem economic budget. The findings can provide an opportunity for greenhouse gas mitigation without crop yield reduction following the proper irrigation and fertilization regimes in the semiarid region. • Soil acts as a sink of CH 4 in dry land regardless of irrigation and N fertilization. • N 2 O emissions are positively related to quantity of irrigation and N fertilization. • Irrigation scheduling had a minor impact on CO 2 emissions in soils with low organic matter. • We estimated the net ecosystem economic budget considering global warming potential. [ABSTRACT FROM AUTHOR]

• Fate of N fertilizer in different irrigation and fertilization regimes is quantified. • Water and N use efficiencies of mulching cultivated maize were analyzed under different regimes. • A proper irrigation and fertilization regime was proposed for maize in arid region. Irrigation and fertilizer management are essential for sustainable development of agriculture in the arid and semiarid regions. In order to obtain high yield production, over irrigation and fertilization are frequently conducted by the farmer which results in a series of environmental problems in particular in the shallow groundwater areas. In this paper, two-year field experiments were conducted to investigate the effect of irrigation and fertilization regimes on grain yield, water and nitrogen productivity of mulching cultivated maize (Zea mays L.) in the Hetao Irrigation District of China. Two irrigation methods, i.e., drip and border irrigation, with different schedules were manipulated in silt loam soil. The border irrigation included two/three different water levels and drip irrigation was triggered by a tensiometer located at a depth of 25 cm with different matric potentials (−15, −25 and −35 kPa). Three different nitrogen fertilization levels (350, 250 and 150 kg ha−1) were applied under drip irrigation controlled by the matric potential of −25 kPa. Soil water storage variation indicated that the active root zone concentrated at a depth of 35−60 cm in the border irrigated plots and 25−45 cm in the drip irrigated plots. Around 16 % of irrigated water (71 out of 450 mm) and 18 % of supplied nitrogen fertilizer (64 out of 350 kg ha−1) were percolated into deeper zone for the farmer's irrigation and fertilization schedules. Border irrigation water reduced from 450 to 315 mm could decrease the deep percolation without yield reduction. Almost no deep percolation was detected in drip irrigation for three different matric potential controls. The highest yield, water and nitrogen productivity obtained from the drip irrigated plots triggered by matric potential of −15 kPa. Considering yield, water and nitrogen productivity, environmental factors and farmer's net-profit, drip irrigation at the matric potential of −15 kPa with 250 kg ha−1 nitrogen fertilizer or border irrigation of 315 mm is recommended for mulching cultivated maize in silt loam soil in the Hetao Irrigation District. The nitrogen fertilizer schedule in border irrigation is desirable for optimal application. [ABSTRACT FROM AUTHOR]

Continuous applications of lignite bioorganic fertilizer (LBF) to the field have achieved substantial improvements in soil physicochemical properties and crop yields in multiple regions throughout China. However, the effects of LBF on crop growth, and water and fertilizer productivity in saline-sodic farmlands were scarcely understood. Thus, in this study, a two-year field experiment with six treatments including a control treatment without any organic fertilizer (CK), a treatment amended with 21 t ha−1sheep manure (SM), and four treatments amended with 1.5 (LBF1), 3 (LBF2), 4.5 (LBF3), and 7.5 t ha−1 (LBF4) LBF, was conducted in 2019 and 2020 in the Hetao Irrigation District (HID), an area known for its saline-sodic conditions located at the upper Yellow River basin, China. The results showed that the LBF2 and LBF3 treatments improved plant height, leaf area index, and dry biomass by 8–76.7 cm, 0.3–2.4, and 309–402 g plant−1, respectively, in comparison with the CK treatment. The root length, root surface area, and root volume in the LBF2 and LBF3 treatment was 18.3–99.7 m, 464.6–2022.6 cm2, and 7.6–46.4 cm3 larger than that in the CK treatment, respectively. Average yield, water productivity, partial nitrogen productivity, and economical gain in the LBF treatments were up to 2.2 t ha−1, 0.4 kg m−3, 23.6 kg kg−1, and 6100 Chinese Yuan ha−1, respectively, substantially higher than those of the CK treatment. In addition, compared with SM treatment, the LBF2 and LBF3 treatments also significantly improved sunflower growth and water and nitrogen productivity. The results of structural equation model analysis and linear regression analysis showed that LBF2 and LBF3 treatments improved sunflower root growth mainly through improving absorption of soil nitrogen. Furthermore, the root indices had a significant positive relation with the sunflower yield, water productivity, and partial nitrogen productivity. The partial nitrogen productivity, water productivity, yield, and economic profits showed a quadratic relationship with the application rate of LBF. A comprehensive assessment of the partial nitrogen productivity, water productivity, yield, and cost versus economic suggested that an application rate of 3.0–4.0 t ha−1 of the lignite bioorganic fertilizer is optimal for achieving a sustainable improvement of crop yield, water productivity, and partial nitrogen productivity in saline-sodic farmlands. • Sunflower growth in saline-sodic soil was improved by lignite bioorganic fertilizer. • Application of lignite bioorganic fertilizer increased sunflower nitrogen absorption. • Water and nitrogen productivity of sunflower increased by lignite bioorganic fertilizer. • 3.0–4.0 t ha−1 is the optimal application rate of lignite bioorganic fertilizer in the study area. [ABSTRACT FROM AUTHOR]

Soil bulk density (BD) is a parameter dependent on soil texture, compositions of soil minerals and organic matter and the extent of soil compaction. Seasonal freeze/thaw in arid areas with shallow groundwater tables (AASGT) may significantly change BD and hence soil hydrothermal properties and water holding capacity. Therefore, quantifying soil bulk density changes (BDC) under freeze/thaw conditions can improve estimates of soil water-salt dynamics in AASGT. In this study, we conducted field experiments to investigate the soil water-salt dynamics under freeze/thaw conditions from three typical land-use types (i.e., farmland, woodland, and natural land) in the upper Yellow River basin, China. We proposed a method to estimate BDC, which can better describe the soil water-salt dynamics during the freeze/thaw period. Our results showed marked BDC occurred in all layers within the 0-100 cm profile in natural land, while mainly at the 20-80 cm profile in farmland. During the freezing period, BD in farmland and natural land first decreased rapidly and then remained relatively stable until the thawing period started. After that, BD gradually increased during the thawing period. The largest BDC in farmland and natural land were 0.48 g cm -3 (occurring at the 30-40 cm layer) and 0.43 g cm -3 (occurring at the 80-90 cm layer), respectively, close to 30 % of their initial values. The differences in BDC between the three land-use types were mainly owing to their differences in groundwater table depth, initial soil salt concentration, soil texture, and surface coverage conditions. Moreover, in farmland and natural land, ignoring BDC resulted in different degrees of overestimation or underestimation in soil water content, water fluxes, and soil hydrothermal properties in the selected soil layers. This study demonstrates that considering BDC can improve the accuracy of soil water-salt dynamics estimation in AASGT under freeze/thaw conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)